A unique stormwater treatment facility is located at the NW corner of 104th Street and Avondale Road It's called a "bio-swale". It's behind a reddish, metal fence and hard to see, but I've been monitoring it since 2007. Bio-swales treat stormwater by oxygenation and by filtering silt, chemicals and other contaminants.
The left photo shows the swale after a downpour in 2007, prior to the Marchione Administration. It is filled with debris and contaminants. The inlet pipes are clogged and one is buried. This bio-swale is in serious need of maintenance. The right photo was taken in December, 2009. It is in immaculate condition. The swale has been broadened and dug to improve treatment. Old, contaminated soil is removed. The inlet pipe at the "elbow" is visible and functional. Concrete blocks now line the swale walls to prevent erosion. Surrounding vegetation is clipped and cleared. Doesn't it look good!? The city really cares!
This bio-swale is particularly important because it treats stormwater flowing into salmon bearing, Bear Creek. Stormwater flows through two inlet pipes from several upland developments and Avondale Road. It exits the swale to Bear Creek through a culvert under Avondale Road.
It is my understanding: Owners of Avondale Villas (L090117) will use the bio-swale after pre-treatment by "wet-vaults". Based on an earlier 9-lot short plat review (Avondale Crest), the landowner will not have to pay for bio-swale maintenance, but will have to pay for the wet-vaults and their maintenance. I'll confirm.
by Bob Yoder
photos & story
cc: City Planner, Thara Johnson, tmjohnson@redmond.gov
Bob,
ReplyDeleteThe bioswale/pond in your pictures was built by the City to improve stormwater quality in Bear Creek around 20 years ago. The blocks have always been there, we just performed routine maintenance on the pond last fall that exposed them, we are considering future modifications to the facility when funding allows that may improve its function and aesthetic values. I don't expect that the new development proposed nearby will negatively impact the City facility.
_________________________
Steve Hitch, P.E.
Sr. Stormwater Engineer
City of Redmond
Public Works Department
Natural Resources Division
(sent by email)
It's my understanding in talking to a stormwater development engineer that two wet vaults on Avondale Villas will enter the swale for from the inlet pipe at the elbow of the swale. Stormwater from the vaults and Avondale will drain into the swale from said pipe.
ReplyDeleteI noticed there are one or two stormwater "streams" further north on Avondale that drain under Avondale culverts into Bear Creek without pre-treatment by bio-swales.